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Questions and Answers

Dr. SearsMalcolm Sears, nominated Principal Investigator

We have received many questions about this study. This page is a place where we can post the questions and our answers. Some of the questions have been posed by policy and government people, some by the academic community and some by the public. Our web-site was constructed to provide as much detail as possible but please understand that this is also an evolving study where we are looking to build on the knowledge of others while focusing on Canadian results.

We believe strongly in our accountability and thus we have erred on the side of 'too much' rather than 'not enough' information. We are hoping that these Q and A's will summarize the details of the study and we encourage questions that help us explain what we are doing and why. We are particularly keen to comment on questions from the public with a slight caution that we will not be able to comment on specific circumstances. Those questions are best directed to you health care provider. If you are a member of our cohort, we encourage you to contact your study coordinator directly.



When will we know the results of this study?

We will be sharing our data as broadly as possible and, as soon as possible. We have already published several articles and have presented some data at scientific forums. We are constrained by three issues.

  1. We want to make sure the data are correct and we have spent a lot of time making sure that we have valid and consistent data.

  2. We need to rely on our academic partners to take the data and both analyze and report on it correctly. The respected academic process is to have such reports peer-reviewed before the results are shared. This process takes time. In an era of twitter and other instant communication technologies, some people expect quicker results and have asked us to release data in raw form. However, we are finding that our success in capturing lots of data is creating enormous pressure to respond to numerous requests for samples and data.

  3. It is expensive to analyze samples and pull sub-sets of data while respecting the need for data quality, sample integrity and most important, privacy. Our funding did not provide for the analysis of all the samples. We are pleased that affiliated research groups have been given funding to analyze the data and samples. At this time, we are not able to release the data without some form of cost recovery.

What factors contribute to child health and development of allergies and asthma ?

We are very interested in learning how to protect the child and his/her parents. We have an opportunity to describe the characteristics of the indoor environment and also analyze biological samples. We are able to describe the amount of dust in people's home and some of the characteristics of the biological samples (like blood and stool). We are still collecting these samples and, we have sent a small number to various labs. Our efforts are focussed on first getting the samples and putting them in specific formats for analysis. But we need to follow the child (and the parents) to see what develops.

We also understand the importance of context and relevance. For example, all homes have dust. However, perhaps the amount of dust and, what is in the dust, may matter in differing ways. Many companies are selling products that claim to reduce the amount of allergens and dust in the home with the assumption that reducing these particles WILL improve health. Parents have also been told that a 'home can be too clean' and 'that some of the chemicals that are being used to clean are not good for a child'. Others conclude a home that is 'too dusty', because it is filled with carpets or clutter, or a home that is located near a major roadway contributes to the development of asthma and allergies.

We want to assess what things matter, in terms of its eventual association with disease, and then parents can respond. It is one thing to know what chemicals or conditions exist in a home or in the blood of baby or mom's and another thing to understand how these conditions correlate with health at five years. The potential predictive power of this correlation makes the CHILD Study unique to most birth cohort studies and very important to policy people. We have created a page on this web site to discuss the origins of diseases in theoretical terms and concepts.


What is the purpose of the study?

Over the past 30 years there has been an increasing concern about the effects of environment on health.  In particular, since infants spend the majority of their time indoors, there is great interest on how the "built" environment affects the healthy development of our children.  There is evidence suggesting that children’s development is influenced by what the child is exposed to during pregnancy and, in the first few years of life.  Yet, very few studies have collected information about the child prior to and immediately after birth, AND, followed the child into the home environment to measure exposures.  CHILD is one of a few studies in the world that will do this. This is one of the reasons our project was endorsed by world experts prior to receiving government funding. Once completed, our project will establish very important benchmarks.


Why is this research being done?

The indoor environment has become a public health priority as growing evidence suggests that unseen environmental contaminants in our living spaces may have important effects on children’s health and development. Our current knowledge of indoor environments is limited and may differ across Canada. Further, we do not know how these differences link direcly to health outcomes. Almost all of our knowledge is based on supposition and conjecture. We want to determine how the environment interacts with genetic factors to affect children’s health and development. This knowledge will assist industry and policy makers to create healthy indoor environments, thus imporving quality of life for future families. This will improve the quality of life for all children and, their families. We have described our project's many hypotheses and methods throughout this site.


Why is this study necessary?

This is a very important question. Our intent is to provide knowledge to many people. For, example, "what role does the home environment play in the development of allergy and asthma and how does this information change the way we build and furnish our homes?" is a question that would influence builders, building material suppliers as well as those who renovate in anticipation of a new child entering the home. Environment Canada and Health Canada, in partnership with CHILD, are keenly interested in developing new techniques for spatial characterization of pollutant levels and chronic exposure estimation. Additionally, Canadian Mortgage and Housing Corporation, another CHILD partner, has strong interest in the study because of the potential that findings will provide information relevant to building standards and design. Our scientific community is interested in knowing what influences lung growth and development in infancy and early childhood. As well, the questions, 'do early childhood infections decrease or increase the risk of allergy and asthma", and 'does the use of antibiotics in early development affect later development?' are important to medical providers and concerned parents..


What restrictions have been placed upon you as you work to complete the study and, what do you see as the project's limitations?

This is a study that is observational and we have no restrictions placed upon us in terms of what we observe. We remain highly respectful of the privacy and ethical conditions that were placed on us by 9 individual and independent ethics review panels. The federal government (through its agency called the Canadian Institute of Health Research (CIHR)) provided funding for this study and our project was extensively and comprehensively peer-reviewed by independent experts before we were approved.

We chose to recruit a "healthy" population rather than an "at risk" population and chose to recruit at multiple sites throughout Canada. If we only recruited mothers who were likely to have children who would, in turn, develop asthma and allergy (a high risk cohort), our results would not be generalizable to the population. We would also likely miss factors that determine genetic risks in those not at high risk.

We are pleased to say that the spirit of generosity for research volunteers in Canada continues to impress us. We would like to acknowledge those that have agreed to participate in the study. We are creating a "made in Canada, for Canadians" research program.


Why study only asthma and allergies, why not study the origins of heart disease, diabetes or obesity?

CHILD is focused on doctor diagnosed asthma and development of allergies. With that in mind, we will have a multitude of different data points including questionnaires and biological samples. With this breadth of data, we have the potential to ask other questions. Since this is a government funded study, we would be delighted to work with other people exploring other diseases. Canada currently has a few cohorts that are looking at specific aspects of childhood development but nothing that compares to the CHILD project. It is our hope to build linkage with some of these cohorts and, with appropriate privacy safeguards, develop powerful databases to examine multiple epidemiologic questions in a wide variety of diseases. This may eventually include chronic disorders such as adult diabetes, cancer, obesity, hypertension and cardiovascular disease, making the CHILD cohort a major national resource for current and future environmental studies.


Don't we already know that the environment causes people to get allergies and asthma, so why do we need another study to show this?

People have made associations based on retrospective observation and many Canadian's are being sold home improvement products that are described as "better" for their health. However, we don't know some very fundamental things. For example, does it matter IF a child is exposed, to WHICH environmental triggers, WHEN and, in WHAT concentration? As well, does exposure in the womb and / or the first 18 months of life subsequently affects the child at age 3, 4 or 5 and, what do we know about modifying the built environment to reduce the severity and permanency of the consequences? We study the exposures, the timing of those exposures and the longer term clinical impact (to age 5). This is the unique aspect of our study and, based on the independent and ongoing review of world experts, our study is likely unique in the world and has the potential of offering significant practical contributions.


It seems like every major country has a birth cohort and we have a number of birth cohort studies in Canada. What is unique about your study?

Simply stated - size, design and scope.

We have an exciting opportunity to look at the development of Canadian children raised in a variety of Canadian households. It is not a study based on a small sample size or in one province. We are a longitudinal study where we follow 3500 children to age five. Second, it surprises people when we remind people that we have a cohort of 3500 moms with a tremendous amount of data being collected. We are following our subjects (parents and children) for five years and this is a major difference to many birth cohort studies.

Although other birth cohorts exist in other countries, this study will be unique to our Canadian experience. Our research study takes into account that substantial information and research that has been produced from international cohorts are applicable to Canada. We are not looking to merely confirm that knowledge; we intend to add to the knowledge through our unique approach, including looking at "gene by environment" interactions and the early development of lung function.


If Canada has so many cohorts, why didn't you combine with other cohorts from the outset? Would this have made sense?

Yes. The key, however, is what is the burden on the mom and most importantly, on the baby. It would have been great if we could recruit one large cohort but our friends, who were setting up other cohorts had important data points to collect that, when added to ours, placed too high a burden on the participants. For example, we would not be able to obtain enough blood samples from baby to satisfy all areas of interest or exploration. Our project's approval was based on a extensive peer-review and we had to focus on the expectation for an intensive study with measurable outcomes. We talked with many groups and we mutually agreed that we could not burden the participant beyond a certain limit.

That being said, we are recruiting in four provinces, with different environmental exposures and demographics. Further, each site is undertaking a unique sub-study of its cohort. In a sense, we have four cohorts which have accepted common Standard Operating Procedures (SOPs) and administrative platforms.


Why don't you have a cohort in Quebec?

We originally proposed 7 sites; Vancouver, Edmonton, Winnipeg, Toronto, Hamilton, Halifax and Montreal. Our funding request was fixed at $12M and so we dropped Hamilton (even though the study was based at McMaster University in Hamilton) then Halifax and, then reluctantly, Montreal. We had to drop Montreal because we could not afford the cost of operating in both English and French. We sought funding to translate our materials but were not successful. It was always our goal to have a group in Quebec.


Why are you not studying the on-reserve Aboriginal population who seem to have a higher burden of disease?

We have 2 sites, Edmonton and Winnipeg, that draw from many different groups - including those who indicate aboriginal status. We also have people in Vancouver and Toronto who also report aboriginal heritage. Although we are collecting "ethnicity", we are not focussing on a specific group. We discussed developing an "on-reserve" aboriginal cohort but decided against it for two reasons. First and most importantly, we wanted to study the general population rather than a specific sub-group. Second, we would need to spend a time consulting with the local elders to make sure that they understood why we wanted to study their communities. This consultation would be essential in order to learn how to engage the community most respectively and, ultimately gain their trust and approval. Our funding did not afford us the time to conduct these critical discussions.

We would be delighted to be invited to talk to the aboriginal communities and explore opportunities to bring our methods, tools and assessments to study healthy child development within an on-reserve community. This however, is not part of our initial mandate.


What are your plans for knowledge transfer?

Knowledge transfer is one of the key "buzz-words" in research -- the other is "research translation". The funding for our study came from a series of institutes within the federal government. This signalled to us that our friends developing policy in government were interested in working with us. We have had ongoing interactions with some of these groups and, have teamed with others in terms of having samples analyzed. However, we are hoping that we can share this study within government in such a way as it is mutually beneficial.

The study is supported by 4 Universities and over 44 academic scientists. We will publish the results and report on our study during various conferences which is what we do well. Some have suggested we should develop a broader media strategy to take advantage of social media technology and different forms of reporting -- blogs and newsletters. The limiting factor is that we do not have a budget line for "publicity" nor for purchasing the expertise of media experts to assist us with this endeavour. Even this web site was developed using "in-house" expertise.

We believe we have a great story to tell and a unique opportunity to understand the lives of ordinary Canadians. We have recruited a cohort of 3500 children from pre-birth to age 3 and will follow the kids until age 5. We have a cohort of 3500 moms and 2800 dads, which we hope to follow until age 5. We will have over 500,000 data points including questionnaires and biological samples. We will have described the building characteristics of 3500 household in Canada, including environmental sampling. We are open to discussing innovative ways to present our work.


What is the economic benefit of conducting this study?

Besides the knowledge gained on healthy child development we see some secondary benefits that are tied to the economy. The federal government legislates standards for housing construction, air ventilation, energy efficiency and safety standards for consumer products that are used in the home. These are sometimes referred to as "modifiable building characteristics". The CHILD study offers a significant benefit to those with the responsibility to develop these standards.

The Government works in collaboration with various industry representatives to develop guidelines that should yield significant health and economic value to Canadians. The government spends millions annually on agencies, departments and consultants to disburse information to many audiences on healthy living. Consider, however, where these agencies and departments obtain their information and how accurately the information addresses Canadian experience. The CHILD study will assist in gathering this data.

Governments understand that home renovation is a huge economic stimulus for the country. The CHILD study has visited homes to specifically and methodically assess the indoor environment of Canadian families. We are conducting a very comprehensive assessment of these built environments. Therefore the secondary benefit of the CHILD study has far reaching implications for the building and home renovation industry. The insight gained through these visits will be beneficial to our government partners, most notably the Canadian Mortgage and Housing Corporation.

Spending on home renovations in Canada has been estimated to be $2.5 billion per month and, according to published reports, totalled $33.4 billion in 2004. As well, in 2005, according to both Statistics Canada and Canada Mortgage and Housing Corporation, total spending on home renovations rose a further six per cent to $38 billion. The reasons for the increase in renovations are varied and attributed to aging housing, an aging population, the high cost of urban land and a strong resale housing market. The key, however, is understanding that renovation spending far outpaces new home construction.

Canadians want to know which building materials are better for the health of the occupants. Additionally, we want to know how specific home conditions can positively or adversely affect our health. Lastly, Canada is a vast country with environments that are unique and, clearly a "one size fits all" policy statement based on limited data does not take into account local circumstances. For example, the Toronto region has a different living environment in comparison to Edmonton or Winnipeg. Vancouver has a different climate than Edmonton, Winnipeg and Toronto. Further, the characteristic of homes - apartment, townhouse, house and location dense urban v. rural affects how homes are constructed and renovated.

CHILD is therefore uniquely positioned to provide data and context to the renovation and housing construction industry. This information will be invaluable to policy makers.


You indicate that you don't have "budget lines" for analyses, yet you receive nearly $6,000,000 in CIHR funding over the period of the study? Why isn't this enough?

In total, we received $12 million over 6 years, including $6 million from CIHR and $6 million from the AllerGen NCE, which is a private entity. When we presented the initial budget to government we anticipated it would cost $48 million, all-in - over 6 years. This included all sample analysis and data extraction. We did not receive the amount we requested so we adjusted our project. We dropped two sites, we reduced our recruitment to 3500 children (our cohort is actually, 9,500 people with babies, moms and dads) and, we scaled back our sample analysis plans. We did not however, change our methods in how we set out to collect and to store the samples. We invested as much of the money on two endeavours; recruitment of the cohort and, the proper collection and storage of the samples. By the time we are done, we expect over 800,000 biological samples and 465,000 questionnaires.

We have heard the critiques that '$12M over six years to recruit 3500 children makes this an expensive study'. We strongly disagree. Recruitment and retention of 3500 children and 3500 moms over 6 years is not an in-expensive proposition when you factor in the cost of paying the out-of-pocket costs for the participants to continue providing us invaluable insight into the development of their children. We recruited our Vanguard cohort in 4 months and our main cohort in 2 years, 10 months. Birth Cohorts are expensive when done correctly - even if the recruitment is done at only one site. When you add several recruiting locations and then place a necessary emphasis on standardizing cohort methods, the costs increase.

In comparison, the research community in the USA proposed a national birth cohort study of 100,000 children followed to age 2. The budget that was approved by Congress for this work is $6.7Billion. In fact, the study was in the planning stage for 10 years and cost nearly $1B before a single person was enrolled. Their goal is to recruit 250 babies a year for four or five years in 105 locations. CHILD was approved in 2005 and in just over three years not only developed the study but recruited a robust cohort of 3500 children.


The federal government has published extensive guidelines concerning indoor air quality. In particular its "Exposure Guidelines for Residential Indoor Air Quality" is widely accessible. So, why do we need to do this study?

We are excited that we can work in partnership with Health Canada and with the Public Health Agency of Canada to combine our collective knowledge. This is important because indoor air regulations are limited by our incomplete understanding of chronic exposures to common pollutants and allergens.

The federal government has published a terrific set of guidelines and the link to these guidelines is - Our study attempts to address one of the important limitations of the government guidelines, which they identified in the document. It is as follows:

"Since research into the health effects of residential indoor air quality is at an early stage, there is a dearth of reliable information on the health effects that result from exposure to the low levels and mixtures of contaminants likely to be found. In most cases, therefore, the Working Group relied upon the results of laboratory experiments using animals, clinical studies with human volunteers, and epidemiological investigations of urban air pollution and the occupational environment. The results of epidemiological and clinical studies are the most relevant for establishing acceptable levels of exposure of humans to air pollutants. Nevertheless, the application of each of these types of study involves a number of assumptions and hence uncertainty in the derived dose-response relationships." (citation)



How do we get access to the samples?

The samples were obtained based on the current grant to the CHILD Study. Distribution of the samples is not a funded line-item in the budget. Therefore, we will charge an administrative fee to release the samples (or questionnaire data). If a researcher has obtained an independent grant to analyze the samples, this should include an administrative fee to obtain the aliquots or questionnaire data. If a researcher wishes to use the data to support a grant application where CHILD receives some of the funding, we will work with you to obtain the data you need and may (depending on the benefit to CHILD) waive the fees.

All samples and data released remain the property of CHILD and thus the researcher is obligated to share results of the analysis. This serves two purposes; we need to add the findings back into the database and, we need to verify that the analysis has academic rigour. Release of samples or questionnaire data requires evidence of the researcher making the request to do it efficiently with the fewest number of samples, timeliness, evidence of use of appropriate and valid techniques that have undergone academic review and are standardized. We cannot release data or samples that contradict our privacy and ethical requirements.


Can we have access to your SOP's ?

Yes, if you are one of our investigators and the purpose of the request supports the work of the study. We relied extensively on "in-kind" contributions from many within our academic community when writing grants, responding to peer-reviewer comments and creating the various SOP's. Those that contributed to the project and who will bring further value to the project are able to access the SOPs. Requests for SOP's from other groups will be reviewed by the project Executive. We recognize that, as our funding was obtained through government, we have an obligation to give back to our academic community.


Will your data be "open-source" ? If not, why not?

A slight digression into definitions. "Open-source" and "free" are not the same thing.

We developed our databases to be very robust and extractable working with a private company called "HealthDiary". Initially, we used paper based questionnaires and then entered the results into a database. This was labor intensive, but the double entry manual process allowed us to learn about and then improve our questionnaires. Once we were satisfied, we then migrated the process to be "web-enabled" electronic data entry, so that the participants could enter their data directly rather than on paper. We also manually check each electronic submission for completeness and accuracy.

We developed our databases to allow for record extraction into SPSS and SAS formats and we adopted an international data variable naming convention based on open source standards. This will allow us to add our data. Since the government, through its grants to us, paid for the collection of the data, we have a proud obligation to share the data when requested for scientific purposes.


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